1. Field Of The Invention
The invention herein pertains to machines and apparatus for sewing, and particularly to commercial multi-head sewing machines which utilize pantographs for embroidering and stitching along multiple stations.
2. Description Of The Related Art
Multi-head sewing machines have been used for many years in industry for embroidering shirts, caps and other articles and for placing trademarks on several garments and other articles simultaneously. In order to insure identical stitching, multi-head sewing machines employ computer driven pantographs which allow all the sewing heads to perform the identical stitch simultaneously, for example at ten or more sewing stations (sewing heads). As customers have become more and more demanding regarding the precision of the stitching or embroidery work, various improvements have been made to rectangular and single rail or T-shaped pantographs. However, in high velocity embroidering on multi-head sewing machines, it is not uncommon for the stitch or pattern to be "out of register" at various sewing heads. This can be due in part to various reasons one of which is the pantograph slightly bending or buckling during rapid movement. Such buckling or warping by the pantograph can cause unacceptable embroidering and can be quite costly at sewing machine speeds of seven hundred fifty stitches per minute or more which is not uncommon with modern sewing equipment. In addition to problems associated with the movement of the pantograph, it has also been found that the mechanisms by which the embroidery hoops are held on the machine are often not properly secured and many times the embroidery hoops slip or slightly move during stitching. This also can contribute to an unacceptable embroidery design or pattern. Additionally, there has also been a need in the past to develop hoop assembly holding devices for pantographs which can be quickly and easily exchanged so the machine operators can embroider baseball caps for example in the morning and that afternoon can embroider tubular goods such as sweatshirts, with only minimal machine down-time.
Thus, with the problems and disadvantages of prior art sewing and embroidering equipment, the present invention was conceived and one of its objectives is to provide a multi-head sewing machine apparatus having a drive mechanism which accurately and efficiently moves a pantograph on a sewing machine table.
It is another objective of the present invention to provide a drive mechanism for a pantograph as used on a high speed multi-head sewing machine which will prevent the pantograph from warping or bending during rapid directional changes.
It is still another objective of the present invention to provide an improved pantograph which includes a reinforced ribbed drive end for more accurate, positive pantograph movement.
It is also an objective of the present invention to provide a multi-purpose holding bracket for a pantograph whereby cap frames or tubular article frames can be affixed thereto and can be easily and rapidly exchanged as desired with minimal labor.
It is yet another objective of the present invention to provide a hoop support boom which will rigidly hold an embroidery hoop assembly and which will securely engage the multi-purpose holding bracket.
It is also another objective of the present invention to provide improved hoop ears for embroidery hoops which will provide a more stable hoop position of the hoop assembly on the pantograph during high speed embroidering.
It is an additional objective of the present invention to provide a multi-purpose holding bracket having a rapid releasable, slidable frame receiver for securely holding cap frames or the like.
Various other objectives and advantages of the present invention become more apparent to those skilled in the art as a more detailed presentation is set forth below.